Expert calls for closure of California nuclear power plant

LOS ANGELES >> A senior federal
nuclear expert is urging regulators to shut down California's last
operating nuclear plant until they can determine whether the facility's
twin reactors can withstand powerful shaking from any one of several
nearby earthquake faults.

Michael Peck, who for five years was
Diablo Canyon's lead on-site inspector, says in a 42-page, confidential
report that the Nuclear Regulatory Commission is not applying the safety
rules it set out for the plant's operation.

The document, which
was obtained and verified by The Associated Press, does not say the
plant itself is unsafe. Instead, according to Peck's analysis, no one
knows whether the facility's key equipment can withstand strong shaking
from those faults -- the potential for which was realized decades after
the facility was built.

Continuing to run the reactors, Peck writes, "challenges the presumption of nuclear safety."

Peck's
July 2013 filing is part of an agency review in which employees can
appeal a supervisor's or agency ruling -- a process that normally takes
60 to 120 days, but can be extended. The NRC, however, has not yet
ruled. Spokeswoman Lara Uselding said in emails that the agency would
have no comment on the document.

The NRC, which oversees the
nation's commercial nuclear power industry, and Diablo Canyon owner
Pacific Gas and Electric Co., say the nearly three-decade-old reactors,
which produce enough electricity for more than 3 million people
annually, are safe and that the facility complies with its operating
license, including earthquake safety standards.

PG&E spokesman
Blair Jones said the NRC has exhaustively analyzed earthquake threats
for Diablo Canyon and demonstrated that it "is seismically safe." Jones
said in an email that the core issue involving earthquake ground motions
was resolved in the late 1970s with seismic retrofitting of the plant.

The
disaster preparedness of the world's nuclear plants came into sharp
focus in 2011, when the coastal Fukushima Dai-ichi plant in Japan
suffered multiple meltdowns after an earthquake and tsunami destroyed
its power and cooling systems. The magnitude-9 earthquake was far larger
than had been believed possible. The NRC has since directed U.S.
nuclear plants to reevaluate seismic risks, and those studies are due by
March 2015.

The important of such an analysis came into sharp
focus on Sunday when a magnitude 6.0-earthquake struck in Northern
California's wine country, injuring scores of residents, knocking out
power to thousands and toppling wine bottles at vineyards.

Environmentalists
have long depicted Diablo Canyon -- the state's last nuclear plant after
the 2013 closure of the San Onfore reactors in Southern California -- as
a nuclear catastrophe in waiting. In many ways, the history of the
plant, located halfway between Los Angeles and San Francisco on the
Pacific coast and within 50 miles of 500,000 people, has been a costly
fight against nature, involving questions and repairs connected to its
design and structural strength.

What's striking about Peck's
analysis is that it comes from within the NRC itself, and gives a rare
look at a dispute within the agency. At issue are whether the plant's
mechanical guts could survive a big jolt, and what yardsticks should be
used to measure the ability of the equipment to withstand the
potentially strong vibrations that could result.

The conflict
between Peck and his superiors stems from the 2008 discovery of the
Shoreline fault, which snakes offshore about 650 yards from the
reactors. A larger crack, the Hosgri fault, had been discovered in the
1970s about 3 miles away, after the plant's construction permits had
been issued and work was underway. Surveys have mapped a network of
other faults north and south of the reactors.

According to Peck's
filing, PG&E research in 2011 determined that any of three nearby
faults -- the Shoreline, Los Osos and San Luis Bay -- is capable of
producing significantly more ground motion during an earthquake than was
accounted for in the design of important plant equipment. In the case
of San Luis Bay, it is as much as 75 percent more.

Those findings
involve estimates of what's called peak ground acceleration, a
measurement of how hard the earth could shake in a given location. The
analysis says PG&E failed to demonstrate that the equipment would
remain operable if exposed to the stronger shaking, violating its
operating license.

The agency should shut the facility down until
it is proven that piping, reactor cooling and other systems can meet
higher stress levels, or approve exemptions that would allow the plant
to continue to operate, according to Peck's analysis.

Peck
disagreed with his supervisors' decision to let the plant continue to
operate without assessing the findings. Unable to resolve his concerns,
Peck in 2012 filed a formal objection, calling for PG&E to be cited
for violating the safety standards, according to his filing. Within
weeks, the NRC said the plant was being operated safely. In 2013 he
filed another objection, triggering the current review.

The NRC
says the Hosgri fault line presents the greatest earthquake risk and
that Diablo Canyon's reactors can withstand the largest projected quake
on it. In his analysis, Peck wrote that after officials learned of the
Hosgri fault's potential shaking power, the NRC never changed the
requirements for the structural strength of many systems and components
in the plant.

In 2012, the agency endorsed preliminary findings
that found shaking from the Shoreline fault would not pose any
additional risk for the reactors. Those greater ground motions were "at
or below those for which the plant was evaluated previously," referring
to the Hosgri fault, it concluded.

Peck, who holds a doctorate in
nuclear engineering and is now a senior instructor at the NRC's
Technical Training Center in Tennessee, declined to comment on the
filing.

Earthquake faults and nuclear power plants have been
uneasy neighbors in the state for decades. The Humboldt Bay plant in
Northern California, which was within 3,000 yards of three faults, was
shut down in 1976 to refuel and reinforce its ability to withstand
possible earthquakes.

Restarting it became more difficult and costly than projected -- it never reopened.

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lokelawrote:

Shut them down. Better safe then sorry. Remember Fukushima?

on August 25,2014 | 06:46AM

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fiveowrote:

All of the nuclear power plants need to be shut down. As what happened
in Fukushima, they are all vulnerable to a power failure due to earthquake,
EMP attack or any other kind of natural disaster. No power, means no cooling
of the nuclear reactor which then means meltdown and explosion thus releasing
deadly radiation for eons to come. These plants do have generators which can
provide power but only for a very short period of time.